OPERATION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

Abstract

To realize the improvement of combustion while simplifying calculation and reducing the number of parts in a operation control device of an internal combustion engine which controls an operation state of an internal combustion engine based on a control map which uses a factor changing corresponding to the operation state of the internal combustion engine as a variable, wherein the factor is an angular-velocity change quantity of a crank angle. [Means for Resolution] Out of reluctors 6 mounted on a crankshaft 4, a front end portion 6a and a rear end portion 6b of at least one reluctor 6 along the rotational direction of the crankshaft 4 are detected by a pulser pick-up 7 in response to the rotation of the crankshaft 4, and an arithmetic operation means 11 calculates an angular-velocity change quantity of the crank angle based on an interval of pulses from a pulser pick-up 7. [Selected Drawing] Fig. 1

Full Text

[Designation of Document] Specification
[Title of the Invention] OPERATION-CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE
[Technical Field] [0001]
The present invention relates to an operation control device of an internal combustion engine which controls an operation state of the internal combustion engine based on a control map which uses a factor changed in response to the operation state of the internal combustion engine as a variable, and uses an angular-velocity change quantity of a crank angle as the factor.
[Background Art]

To realize the improvement of combustion of an internal combustion engine such as the improvement of fuel consumption, through patent document 1, patent document 2 or the like, there has been known an operation control device which performs an operation control of an internal combustion engine by changing over a control map using a measured intake negative pressure, an estimated intake negative pressure or the like obtained by calculation based on other measured value as a factor.
[Patent document 1] JP-A-2000-265894
[Patent document 2] JP-A-2004-108289 [Disclosure of the Invention]

[Problems that the Invention is to Solve]
[0003]
However, in the above-mentioned operation control device disclosed in the patent document 1 and the patent document 2, due to the provision of a negative pressure sensor or other sensors necessary for estimating the intake pressure and the like, a relatively complicated calculation using various factors becomes necessary. Further, the detection of a crank angle also requires the detection of a plurality of pulses using a plurality of reluctors mounted on a crankshaft. On the other hand, in performing the operation control of the internal combustion engine for improving the combustion, if the calculation can be simplified and the number of parts can be reduced, it is also possible to apply the operation control of the internal combustion engine to a relatively low-cost motorcycle leading to the further improvement of environment.
[0004]
The invention has been made under such circumferences, and it is an object of the invention to provide an operation control device of an internal combustion engine which can realize an operation control aiming at the improvement of combustion while simplifying the calculation and reducing the number of parts. [Means for Solving the Problem]
[0005]

To achieve the above-mentioned objects, the invention according to claim 1 is characterized in that, an operation control device of an internal combustion engine which controls an operation state of an internal combustion engine based on a control map which uses a factor changed in response to the operation state of the internal combustion engine as a variable and uses an angular-velocity change quantity of a crank angle as the factor, the operation control device comprising, a pulser pick-up which outputs pulses upon detection of a front end portion and a rear end portion of at least one reluctor mounted on a crankshaft along the rotational direction of the crankshaft in response to the rotation of the crankshaft, and an arithmetic operation means which calculates the angular-velocity change quantity of the crank angle based on an interval of pulses outputted from the pulser pick-up upon detection of the front end portion and the rear end portion.
[0006]
The invention according to claim 2 is, in addition to the constitution of the invention described in claim 1, characterized in that the reluctor which detects the front end portion and the rear end portion using the pulser pick-up is mounted on the crankshaft with the crank angle before a compression-stroke top dead center.
[0007]
The invention according to claim 3 is, in addition to

the constitution of the invention described in claim 1, characterized in that the reluctor which detects the front end portion and the rear end portion using the pulser pick-up is mounted on a rotor of a generator for detecting reference ignition timing of the internal combustion engine, and the reluctor is used for the detection of the reference ignition timing and the calculation of the angular-velocity change quantity of the crank angle. [Advantage of the Invention]
[0008]
According to the invention described in claim 1, the front end portion and the rear end portion of one reluctor along the rotational direction of the crankshaft are detected by the pulser pick-up in response to the rotation of the crankshaft, and the angular-velocity change quantity of the crank angle is calculated by the arithmetic operation means based on the interval of pulses outputted from the pulser pick-up thus controlling the operation state of the internal combustion engine using the control map which uses the angular-velocity change quantity as a variable. Accordingly, it is possible to reduce the number of parts necessary for detecting the factor changed in response to the operation state of the internal combustion engine and, at the same time, it is possible to realize the improvement of combustion by simplifying the calculation.

[0009]
According to the invention described in claim 2, the arithmetic operation means obtains the angular-velocity change quantity at a crank angle before a compression-stroke top dead center. Accordingly, by obtaining the angular-velocity change quantity at a portion where the angular-velocity change quantity is relatively large, it is possible to obtain the accurate angular-velocity change quantity.
[0010]
Further, according to the invention described in claim 3, the reluctor which is mounted on the rotor of the generator for detecting reference ignition timing of the internal combustion engine is used for the detection of the reference ignition timing and the calculation of the angular-velocity change quantity, and hence, it is possible to perform the operation control of the internal combustion engine using only one reluctor of the generator. Accordingly, for example, the invention allows the use of an inexpensive generator for an internal combustion engine which detects only reference ignition timing and does not perform an ignition timing control and a fuel injection quantity control thus easily realizing the reduction of cost of the internal combustion engine which can perform the operation control such as the ignition timing i control or the fuel injection quantity control.

[Best Mode for Carrying out the Invention]
[0011]
Hereinafter, a mode for carrying out the invention is explained based on an embodiment of the invention shown in attached drawings.
[0012]
Fig. 1 to Fig. 6 are views showing a first embodiment of the invention, wherein Fig. 1 is a view showing the overall constitution of an operation control device of an internal combustion engine, Fig. 2 is a view showing the relationship between reluctors and output timing of a pulser pick-up, Fig. 3 is view showing the relationship among strokes of the internal combustion engine, the reluctors and crank angular velocity, Fig. 4 is a flowchart showing control steps executed by a control unit, Fig. 5 is a view showing a control map which determines ignition timing, and Fig. 6 is a view showing a change of the crank angular velocity in the vicinity of the compression-stroke top dead center.
[0013]
First of all, in Fig. 1, a carburetor 2 is interposed in an intake pipe 1 of an internal combustion engine EA which is a 4-cycle engine, intake-air quantity and fuel supply quantity are controlled by the carburetor 2, and fuel is burnt in an internal combustion engine EA due to an ignition of an ignition plug 3.

[0014]
A rotor 5 of a generator ACG is fixed to a crankshaft 4 of the internal combustion engine EA, and one reluctor 6 is mounted on the rotor 5 at a crank angle position determined based on reference ignition timing before a compression-stroke top dead center . The reluctor 6 is detected by a pulser pick-up 7 in response to the rotation of the crankshaft 4. The pulser pick-up 7 outputs pulses by detecting a front end portion 6a and a rear end portion 6b of the reluctor 6 along the rotational direction 13 of the crankshaft 4 in response to the rotation of the crankshaft 4. [0015]
Here, as shown in Fig. 2, the pulser pick-up 7 outputs a rising pulse in response to the detection of the front end portion 6a of the reluctor 6 along the rotational direction 13 corresponding to the rotation of the crankshaft 4, and a falling pulse in response to the detection of the rear end portion 6b of the reluctor 6 along the rotational direction 13 corresponding to the rotation of the crankshaft 4. When
the reluctor 6 is arranged within a range of an angle 9 about an axis of the crankshaft 4, the pulser pick-up 7 outputs the rising pulse and the falling pulse at an interval of the crank angle 9. Assuming a time between output timings of the rising pulse and the falling pulse as T and assuming average angular velocity between the rising pulse and the falling pulse

indicated by a solid line in Fig. 3, and the crank angular velocity co at the time of low torque and low intake air amount is changed as indicated by a broken line in Fig. 3 . The higher the output torque and the larger the intake air amount, the
change of the crank angular velocity co is increased. [0018]
An output signal of the pulser pick-up 7 is inputted to an electronic control unit 8A. The electronic control unit 8A includes a CPU 9A and a memory 10A which is constituted of a RAM, a ROM and the like. The CPU 9A has a function of an arithmetic operation means 11 which calculates the rotational speed of the internal combustion engine EA and the angular-velocity change quantity of the crank angle based on an interval between a rising pnl se and a falling pulse outputted from the pulser pick-up 7, and a function of a processing means 12A which determines ignition timing of the ignition plug 3 based on a calculation result of the arithmetic operation means 11. Further, in the memory 10A, a correction coefficient map of a correction coefficient for correcting ignition timing in response to an intake air temperature and an engine temperature (or cooling water temperature) is pre-stored. [0019]
The electronic control unit 8A controls the ignition timing of the ignition plug 3 in accordance with steps shown in Fig. 4, wherein processing in step SI to step S4 is executed

by the arithmetic operation means 11, and processing in step S5 to step S7 is executed by the processing means 12.
[0020]
The step SI shown in Fig. 4 is provided for calculating the rotational speed Ne (coa) of the internal combustion engine EA. In this embodiment, the rotational speed Ne (coa) of the internal combustion engine EA is calculated based on a time T required for counting the predetermined number of times N of one of rising and falling pulses detected by the pulser
pick-up 7. That is, the rotational speed coa is calculated by a following equation, wherein N is "2", for example.
coa=Nx360°/T
[0021]
In step S2, a compression-stroke top dead center is determined. Here, the pulser pick-up 7 is configured to output the rising pulse and the falling pulse at a crank angle which determines the ignition timing before the compression-stroke top dead center and at a crank angle before a stroke-overlapping top dead center between the exhaust stroke and the intake stroke .
However, as shown in Fig. 3, the crank angular velocity co at the crank angle before the compression-stroke top dead center is smaller than the average value of the crank angular velocity
coa, and the crank angular velocity co before the stroke-overlapping top dead center is larger than the average
value of the crank angular velocity coa and hence, it can be

be performed without calculating the intake air amount. However, the intake air amount can be simply estimated using
the above-mentioned angular-velocity change quantity Aco. An estimation technique of the intake air amount is explained hereinafter. [0027]
A torque change AN of the internal combustion engine EA is the difference between a net torque and a traveling resistance torque of the internal combustion engine EA. Assuming an output torque of the internal combustion engine EA attributed to the pressure in the cylinder as Ncyiindere.work/ a friction resistance torque of the internal combustion engine EA as Nfriction and a traveling resistance torque as Nioacu the relationship between the torque change AN and an equivalent moment of inertia I of the crankshaft 4 can be expressed by a following equation of motion. [0028]
AN= (Ncylindere.work-Nfriction) -Nload=I- (dCO/dt) ... (1)
Here, assuming the pressure in the cylinder as Pcyiinder/ an inner diameter of the cylinder as B, a mass of gas in the combustion chamber as M, a gas constant as R, gas absolute temperature as T, a cylinder inner volume as V, and an effective diameter in torque calculation as r, the output torque of the internal combustion engine EA is expressed by a following equation.

above-mentioned equation (4) is expressed by a following equation (6) .
Aco/Ax=M-T-(l/I)-(R/V)-(rc/4)B2-r ... (6)
Here, M is an air amount sucked into the combustion chamber, and ( (1/1) • (R/V) • (7t/4) B2-r) is a fixed value . Assuming that Ax is fixed when the rotational speed Ne of the internal combustion engine EA is equal, the relationship AcoocM-T is established, while when the intake temperature T is fixed, the
relationship AoocM is established. The intake air amount can be easily estimated from the angular-velocity change quantity
Aco obtained based on the pulse outputted from the pulser pick-up 7 for detecting the reluctor 6.
[0031]
Next, the manner of operation of the first embodiment is explained. Upon detection of the front end portion 6a and the rear end portion 6b along the rotational direction 13 of one reluctor 6 mounted on the crankshaft 4 corresponding to the rotation of the crankshaft 4, the pulser pick-up 7 outputs rising and falling pulses. Based on an interval between the rising and falling pulses, the arithmetic operation means 11 in the CPU 9A of the electronic control unit 8A calculates the rotational speed Ne of the internal combustion engine EA and
the angular-velocity change quantity Aco of the crank angle. Based on a result of the calculation of the arithmetic operation means 11, the processing means 12A controls an operation state

calculation of the angular-velocity change quantity Aco of the crank angle whereby the operation control of the internal combustion engine EA can be performed using only one reluctor 6 of the generator ACG. Due to such an operation control, an inexpensive generator for an internal combustion engine which detects only reference ignition timing and is not subject to an ignition timing control and a fuel-injection quantity control can be diverted thus facilitating the reduction of cost of the internal combustion engine EA which performs the operation control such as the ignition timing control or the fuel injection quantity control.
[0034]
Fig. 7 shows a second embodiment of the invention, wherein parts corresponding to the parts of the above-mentioned first embodiment are only shown in the drawing with the identical symbols, and their detailed explanation is omitted.
[0035]
An internal combustion engine EB includes an ignition plug 3 and a variable valve mechanism 14 for changing an operation characteristic in response to an operation state. In the internal combustion engine EB, a throttle valve 17 is rotatably arranged on a middle portion of an intake pipe 16 which introduces air cleaned by an air cleaner 15 into the internal combustion engine EB. Fuel is fed to the inside of the intake pipe 16 by a fuel injection valve 18 downstream of

the throttle valve 17. Further, an exhaust-gas recirculation device 20 is arranged between the intake pipe 16 downstream of the throttle valve 17 and an exhaust pipe 19 which guides an exhaust gas discharged from the internal combustion engine EB.
[0036]
In response to the rotation of a crankshaft 4 of the internal combustion engine EB, in the same manner as the above-mentioned first embodiment, a pulse signal is outputted from a pulser pick-up 7 for detecting a single reluctor. An output signal of the pulser pick-up 7 is inputted to an electronic control unit 8B. The electronic control unit 8B includes a CPU 9B and a memory 10B which is constituted of a RAM, a R.OM and the like. The CPU 9R has a function of an arithmetic operation means 11 which calculates the rotational speed of the internal combustion engine EB and the angular-velocity change quantity of the crank angle based on an interval between a rising pulse and a falling pulse outputted from the pulser pick-up 7, and a function of a processing means 12B which controls ignition timing of the ignition plug 3, the operation characteristic of the variable valve mechanism 14, injection start timing and an injection quantity of a fuel injection valve 18, and exhaust-gas recirculation start timing and an exhaust-gas recirculation amount by the exhaust-gas recirculation device 20 based on a calculation result of the

arithmetic operation means 11. [0037] That is, based on a control map which uses the
angular-velocity change quantity Aco of the crank angle calculated by the arithmetic operation means 11 of the CPU 9B based on the output signal of the pulser pick-up 7 as a variable, in addition to the ignition timing control of the ignition plug 3 in the first embodiment, the operation characteristic control of the variable valve mechanism 15, the control of the injection start timing and the injection quantity of the fuel injection valve 18, and the control of the exhaust-gas recirculation start timing and the exhaust-gas recirculation amount by the exhaust-gas recirculation device 20 can be executed. Accordingly, the number of parts necessary for detecting factors which are changed in response to the operation state of the internal combustion engine EB can be reduced and, at the same time, the calculation can be simplified thus improving the combustion.
[0038]
Although the embodiments of the invention have been explained heretofore, the invention is not limited to the above-mentioned embodiments and various modifications in design can be made without departing from the invention described in Claims.
[0039]

[Designation of Document] Claims
[Claim 1]
An operation control device of an internal combustion engine which controls an operation state of an internal combustion engine (EA, EB) based on a control map which uses a factor changed in response to the operation state of the internal combustion engine (EA, EB) as a variable, and uses an angular-velocity change quantity of a crank angle as the factor, the operation control device comprising; a pulser pick-up (7) which outputs pulses upon detection of a front end portion (6a) and a rear end portion (6b) of at least one reluctor
(6) mounted on a crankshaft (4) along the rotational direction of the crankshaft (4) in response to the rotation of the crankshaft (4) ; and an arithmetic operation means (11) which calculates the angular-velocity change quantity of the crank angle based on an interval of pulses outputted from the pulser pick-up (7) upon detection of the front end portion (6a) and the rear end portion (6b).
[Claim 2]
An operation control device of an internal combustion engine according to claim 1, wherein the reluctor (6) which detects the front end portion (6a) and the rear end portion
(6b) using the pulser pick-up (7) is mounted on the crankshaft
(4) with the crank angle before a compression-stroke top dead i center.

[Claim 3]
An operation control device of an internal combustion engine according to claim 1, wherein the reluctor (6) which detects the front end portion (6a) and the rear end portion (6b) using the pulser pick-up (7) is mounted on a rotor (5) of a generator (ACG) for detecting reference ignition timing of the internal combustion engine (EA, EB), and the reluctor (6) is used for the detection of the reference ignition timing and the calculation of the angular-velocity change quantity of the crank angle.